Current tritium (T, .sup.3 H) detectors can be divided into two categories: high resolution isotope mass spectrometers located at remote analysis stations, and field units which detect tritium by detecting beta emission from this unstable species. Ion mass speotrometry has been used to detect trace amounts of tritium directly or by an increase in the concentration of its decay product, .sup.3 He. However, a mass resolution of m/.DELTA.m&gt;10.sup.5 is required to separate the tritium mass spectrum from that of .sup.3 He, and accurate measurements of .sup.3 He variation typically require more than one month. The sensitivity, complexity, size and cost of instrumentation having the necessary resolution prohibits its application to real-time, on-site analyses.
As stated, existing fieldable detectors (e.g., ion chambers) measure tritium concentration from detection of its beta emission. However, the presence of other beta-emitting species (e.g., .sup.22 Ra, .sup.41 Ar, or .sup.85 Kr) or gamma radiation can render this measurement ambiguous. Furthermore, due to the relatively long half-life of tritium (12.33 years), a substantial quantity of tritium is required in a sample for real-time measurements employing beta emission. This typically limits the sensitivity of real-time, beta-decay instruments to approximately 0.01 ppb.
On-site detection of deuterium (D, .sup.2 H) using traditional low-mass-resolution mass spectrometry is prohibitive due to the presence of other isobaric (essentially equivalent atomic mass) species such .sup.1 H.sub.2 and .sup.4 He.sup.+2 that make the measurement ambiguous.
Accordingly, it is an object of the present invention to provide a compact, rugged, low-mass-resolution apparatus for real-time quantitative detection of isotopes of hydrogen and helium.
Another object of the present invention is to provide a compact, rugged, low-mass-resolution apparatus for real-time quantitative detection of the molecular form of hydrogen atoms having different isotopic components.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.